Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defect that the oxygen evolution catalyst is prepared without the strontium-doped noble metal oxide in the prior art, thereby providing the oxygen evolution electrocatalyst of the strontium-doped noble metal oxide and the preparation method thereof, wherein the preparation method is simple, the cost is low, and the catalyst activity is good.
Therefore, the technical scheme of the invention is as follows:
a preparation method of an oxygen evolution electrocatalyst of a strontium-doped noble metal oxide comprises the following steps:
(1) mixing metal chloric acid with strontium hydroxide solution at 70-90 ℃;
(2) cooling the mixed solution obtained in the step (1) to 0-30 ℃, centrifuging, and taking a precipitate;
(3) and (3) calcining the precipitate obtained in the step (2) to obtain the oxygen evolution electrocatalyst.
Further, in the step (1), the molar ratio of strontium hydroxide to metal chloric acid is not less than 3: 1.
further, in the step (1), the metal chloric acid is chloro-iridic acid or chloro-ruthenic acid.
Further, in the step (1), the concentration of the metal chloric acid is 0.02-2 mol/L.
Further, in the step (1), the concentration of strontium hydroxide is 0.15-1.7 mol/L.
Further, metal chloric acid and metal oxide nano-particles are mixed to form a suspension, and then the suspension is mixed with a strontium hydroxide solution at 70-90 ℃.
Further, in the step (1), the metal oxide is one of titanium oxide, tin oxide and zirconium oxide.
Further, in the step (1), the molar ratio of metal chloric acid to metal oxide is 1: 0.1-10.
further, in the step (3), the calcination temperature is 400-.
An oxygen evolution electrocatalyst of a strontium doped noble metal oxide prepared according to the above method.
Further, the oxygen evolution electrocatalyst includes a noble metal oxide and strontium oxide having crystal lattice vacancies.
Further, the oxygen evolution electrocatalyst is of a core-shell structure and comprises a core body and strontium oxide coated on the core body and having crystal lattice vacancies, wherein the core body is a noble metal oxide; or the core body is a mixture formed by noble metal oxide and metal oxide; or the core body is a composite structure formed by encapsulating metal oxide by noble metal oxide;
further, the noble metal oxide is iridium oxide or ruthenium oxide; the metal oxide is one of titanium oxide, tin oxide and zirconium oxide.
The technical scheme of the invention has the following advantages:
1. the invention provides a preparation method of an oxygen evolution electrocatalyst of a strontium-doped noble metal oxide, which is characterized in that strontium is precipitated by utilizing the change of the solubility of strontium hydroxide along with the temperature to synthesize the strontium-doped oxygen evolution electrocatalyst.
2. The invention provides an oxygen evolution electrocatalyst prepared by strontium-doped noble metal oxide, wherein non-noble metal strontium (Sr) is doped into a noble metal catalyst, so that the influence on crystal lattices can be generated, the reaction sites of the catalyst are increased, the performance of the catalyst is improved, and the loading amount of noble metal is reduced.
Detailed Description
The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.
The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.
The particle size of the metal oxides, i.e., titanium oxide, tin oxide and zirconium oxide, in the examples and comparative examples was 30 nm.
The overpotential test method comprises the following steps: the overpotential test method comprises the following steps: the voltammetry curve was measured using an electrochemical workstation, and the value of the electrolysis voltage at the corresponding current density was subtracted by the value of the voltage required for the reaction kinetics (1.229V).
The stability test method comprises the following steps: fixing the electrolysis voltage for a period of time, and testing the attenuation value of the current density; or at a fixed current density for a period of time.
Example 1
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridate; preparing 21.85mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the above two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining at 550 deg.C for 2 hr to obtain 0.55g of SrO and IrO2The molar ratio is 1: 2 strontium-doped iridium oxide oxygen evolution electrocatalyst.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential of the catalyst is 0.28V, and the current density is 100mA/cm2The overpotential of the catalyst is 0.66V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays by 5%. FIG. 1 is a schematic diagram of the structure of an oxygen evolution electrocatalyst prepared according to examples 1-8, in which the core is a noble metal oxide and the shell is strontium oxide with crystal lattice vacancies; FIG. 3 is an XRD characteristic spectrum of the oxygen evolution electrocatalyst prepared in this example; fig. 4 is an SEM image of the oxygen evolution electrocatalyst prepared in this example.
Example 2
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridate; preparing 28.45mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the above two solutions, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining at 550 deg.C for 2 hr to obtain 0.86g of SrO and IrO2The molar ratio is 2: 1 strontium-doped iridium oxide oxygen evolution electrocatalyst.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.33V, and the current density was 100mA/cm2The overpotential of the catalyst is 0.74V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays by 5.5%.
Example 3
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
20mL of 0.02mol/L chloroiridate is prepared; preparing 8mL of 0.15mol/L strontium hydroxide solution at 90 ℃; mixing the two, cooling to 30 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 400 ℃ for 4 hours to obtain the strontium-doped iridium oxide oxygen evolution electrocatalyst.
Example 4
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
20mL of 2mol/L chloroiridate is prepared; 100mL of 1.7mol/L strontium hydroxide solution at 70 ℃ is prepared; mixing the two, cooling to 0 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 600 ℃ for 1.5h to obtain the strontium-doped iridium oxide oxygen evolution electrocatalyst.
Example 5
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 0.1mol/L chlororuthenate; preparing 21.85mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining the precipitate at 550 deg.C for 2 hr to obtain SrO and RuO2The molar ratio is 1: 2 strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential of the catalyst is 0.28V, and the current density is 100mA/cm2The overpotential of the catalyst is 0.64V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 6.0%.
Example 6
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 0.1mol/L chlororuthenate; preparing 28.45mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining the precipitate at 550 deg.C for 2 hr to obtain SrO and RuO2The molar ratio is 2: 1 strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.31V and the current density was 100mA/cm2The overpotential of the catalyst is 0.68V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 5.8%.
Example 7
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 1mol/L chlororuthenate; preparing 80mL of 1.0mol/L strontium hydroxide solution at 85 ℃; mixing the two, cooling to 20 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 800 ℃ for 1h to obtain the strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
Example 8
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 0.5mol/L chlororuthenate; 25mL of 1.2mol/L strontium hydroxide solution at 85 ℃; mixing the two, cooling to 20 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 800 ℃ for 1h to obtain the strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
Example 9
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridic acid, and adding 0.002mol of titanium oxide nano particles to form a suspension; preparing 28.45mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the above two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining the precipitate at 550 deg.C for 2 hr to obtain IrO2、SrO、TiO2The molar ratio is 1: 0.5: 1 strontium-doped iridium oxide oxygen evolution electrocatalyst.
The preparation loading is 3mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential of the catalyst is 0.35V, and the current density is 100mA/cm2The overpotential of the catalyst is 0.75V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density attenuation is 4.5 percent; FIG. 2 is a schematic diagram showing the structures of oxygen evolution electrocatalysts prepared in examples 9 to 12, wherein the core is a composite structure formed by encapsulating a metal oxide with a noble metal oxide, and the shell is strontium oxide having crystal lattice vacancies. Fig. 5 is an XRD characteristic spectrum of the oxygen evolution electrocatalyst prepared in this example.
Example 10
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridic acid, and adding 0.01mol of titanium oxide nanoparticles to form a suspension; preparing 28.45mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the above two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, calcining the precipitate at 550 deg.C for 2 hr to obtain IrO2、SrO、TiO2The molar ratio is 1: 0.5: 5 strontium-doped iridium oxide oxygen evolution electrocatalyst.
Example 11
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 0.02mol/L chlororuthenate, and adding 0.004mol of tin oxide nano-particles to form a suspension; preparing 15mL of 0.15mol/L strontium hydroxide solution at 90 ℃; mixing the two, cooling to 30 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 400 ℃ for 4 hours to obtain the strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
The preparation loading is 3mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.33V, and the current density was 100mA/cm2The overpotential of the catalyst is 0.74V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 5.6%.
Example 12
Preparation of oxygen evolution electrocatalyst of strontium-doped ruthenium oxide
Preparing 20mL of 2mol/L chlororuthenate, and adding 0.004mol of zirconium oxide nano particles to form a suspension; preparing 80mL of 1.7mol/L strontium hydroxide solution at 70 ℃; mixing the two, cooling to 0 ℃, centrifuging at 10000rpm, taking the precipitate, and calcining the precipitate at 600 ℃ for 1.5h to obtain the strontium-doped ruthenium oxide oxygen evolution electrocatalyst.
Comparative example 1
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridate; preparing 21.85mL of 0.6mol/L strontium hydroxide solution at 60 ℃; mixing the two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, and calcining the precipitate at 550 deg.C for 2 hr.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential is 0.39V and the current density is 100mA/cm2When the catalyst is used, the overpotential of the catalyst is 0.81V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 7.1%.
Comparative example 2
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridate; preparing 21.85mL of 0.6mol/L strontium hydroxide solution at 100 ℃; mixing the two, cooling to 20 deg.C, centrifuging at 10000rpm, collecting precipitate, and calcining the precipitate at 550 deg.C for 2 hr.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential is 0.38V and the current density is 100mA/cm2The overpotential of the catalyst is 0.84V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 8%.
Comparative example 3
Preparation of oxygen evolution electrocatalyst of strontium doped iridium oxide
Preparing 20mL of 0.1mol/L chloroiridate; preparing 21.85mL of 0.6mol/L strontium hydroxide solution at 80 ℃; mixing the two, cooling to 40 deg.C, centrifuging at 10000rpm, collecting precipitate, and calcining the precipitate at 550 deg.C for 2 hr.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.40V, and the current density was 100mA/cm2The overpotential of the catalyst is 0.83V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 9%.
Comparative example 4
1mol of iridium hydroxide and 0.5mol of strontium hydroxide were mixed and then calcined at 550 ℃ for 2 hours.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.42V, and the current density was 100mA/cm2The overpotential of the catalyst is 0.98V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 11%.
Comparative example 5
Preparing 20mL of 0.1mol/L chloroiridate; preparing 21mL of 0.2mol/L sodium hydroxide solution at 80 ℃; mixing the two solutions, adding 0.01mol titanium oxide nanoparticles (diameter 30nm) to form suspension, cooling to 40 deg.C, centrifuging at 10000rpm, collecting precipitate, and calcining at 550 deg.C for 2 hr. An iridium oxide electrocatalyst supported only by titanium oxide was obtained.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2When the catalyst is used, the overpotential of the catalyst is 0.48V, and the current density is 100mA/cm2When the catalyst is used, the overpotential of the catalyst is 1.08V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays by 10%. The iridium oxide electrocatalyst supported on titanium oxide has poorer performance than the iridium oxide catalyst supported on strontium oxide or strontium oxide + titanium oxide.
Comparative example 6
Preparing 20mL of 0.1mol/L chlororuthenate; preparing 21mL of 0.2mol/L sodium hydroxide solution at 80 ℃; mixing the two solutions, adding 0.01mol titanium oxide nanoparticles (diameter 30nm) to form suspension, cooling to 40 deg.C, centrifuging at 10000rpm, collecting precipitate, and calcining at 550 deg.C for 2 hr. A ruthenium oxide electrocatalyst supported only by titanium oxide was obtained.
The preparation loading is 2.5mg/cm2The oxygen evolution electrode of (1) was tested at a current density of 10mA/cm2The overpotential of the catalyst was 0.44V, and the current density was 100mA/cm2When the catalyst is used, the overpotential of the catalyst is 1.01V; at 100mA/cm2Under the test condition of the current density, after 2.5 hours of stability test, the current density decays to 12%. The titanium oxide-supported ruthenium oxide electrocatalyst has poorer performance than the strontium oxide or strontium oxide + titanium oxide-supported ruthenium oxide catalyst.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.